Solid-state Hg-199 MAS NMR and vibrational spectroscopic studies of dimercury(I) compounds

The solid-state Hg-199 MAS NMR spectra of Hg2X2 (X = Cl, SCN, NCO, CH3CO2, CF3CO2) have been measured, and the infrared and Raman spectra of these com pounds have been recorded and analyzed to further characterize them and to assist in the interpretation of the NMR data. Spinning-sideband analysis ha s been used to determine the Hg-199 shielding anisotropy and asymmetry para meters Delta sigma and eta from the solid-state Hg-199 MAS NMR spectra. in contrast to the case of the corresponding mercury(II) compounds, the shield ing anisotropy is found to be relatively insensitive to the nature of the X group. This is consistent with the view that the electronic environment of the Hg atom in the mercury(I) compounds is dominated by the Hg-Hg bond. Th e changes in the Hg-199 shielding parameters from the mercury(II) to the co rresponding mercury(I) compounds, as well as the changes in these parameter s in the mercury(I) compounds with changes in X, can be interpreted in term s of variations in the local paramagnetic contribution to the shielding ten sor.